1. Field of the Invention
This invention pertains to the field of bioaffecting compositions; more specifically, it pertains to novel carboxylic acid esters and intermediates thereto, to insecticidal compositions containing the novel esters, and to the use of the compositions for controlling insects.
2. Description of the Prior Art
Pyrethrins have long been of interest as insecticides. Since it was discovered that pyrethrins are organic esters, various synthetic modifications have been made in the carboxylic acid and in the alcohol moieties on either side of the ester linkage to produce pyrethroid insecticides. Many of the synthetic pyrethroids are more effective than the natural pyrethrins, and recent modifications have overcome a chronic pyrethrins problem--instability to air and light.
The carboxylic acid moiety in the aforesaid esters has often been a 2,2-dimethyl-1-cyclopropanecarboxylic acid. Several important acids in this class contain substituents other than hydrogen in the 3-position. These 3-substituents include the 2,2-dimethylvinyl group, and the 2-carbomethoxy-2-methylvinyl group, found in the pyrethrins, the 2,2-dihalovinyl group, which appears in many of the recent stable pyrethroids [South African Pat. No. 73/3528], and simply 3,3-dimethyl substitution [Ger. Offen. No. 2,407,024]. It is not necessary that the acid moiety be a cyclopropanecarboxylic acid, however; 2-(4-chlorophenyl)-3-methylbutanoic acid is functionally similar in pyrethroids [Belg. Pat. No. 801.946]. All of these acids, those appearing as the acid moiety in the aforesaid pyrethrins and pyrethroids, are pyrethroid carboxylic acids, chemical structures well known to those skilled in the art.
Many variations in the alcohol moiety of the aforesaid esters have been disclosed also. These alcohols are described in the prior art and are well known. For example, pyrethroids wherein the alcohol moiety is an .alpha.-substutited-3-phenoxybenzyl alcohol have been disclosed [Ger. Offen. Nos. 2,231,312; 2,407,024; 2,547,534]. The relative insecticidal activity of a series of .alpha.-substituted-3-phenoxybenzyl carboxylates has been published [Matsuo, et al., Agr. Biol. Chem., 40, 247 (1976)]. The .alpha.-substituent, monochloromethyl, is disclosed by Matsuo, et al., but this appears to be the only .alpha.-haloalkylphenoxybenzyl alcohol moiety to appear in the aforesaid esters.